A key patent for Remicade (infliximab), a top-selling rheumatoid arthritis drug made by Johnson & Johnson subsidiary Janssen Biotech, is invalid, a federal court has ruled. The decision, which Janssen pledged to appeal, is a victory for Pfizer-owned Hospira Healthcare and Celltrion Healthcare. The companies plan to launch a biosimilar version of Remicade in the U.S. later this year. A federal trial court in Massachusetts found that the antibodies covered by the disputed patent, which expires in 2018, were already disclosed in an earlier patent. In a separate proceeding regarding this patent, the U.S. Patent & Trademark Office came to a similar conclusion, a decision that Janssen is appealing. Meanwhile, the federal court is also considering the validity of a second Janssen patent related to Remicade which expires in 2027. Pfizer’s Hospira has exclusive U.S. marketing rights to an infliximab biosimilar that would be made by Celltrion, a South Korean drugmaker. Remicade is J&J’s best-selling drug. In 2015, this biologic drug generated U.S. sales of nearly $4.5 billion and worldwide sales of almost $6.6 billion.